Question

The following statements are the steps in the catalytic action of an enzyme. Arrange them in correct sequence.
a) The active site of the enzyme, now in close proximity of the substrate, breaks the chemical bonds of the substrate and the new enzyme product complex is formed.
b) The substrate binds tightly to the enzyme, inducing a change in the active site of the enzyme.
c) The enzyme releases the products of the reaction and the free enzyme is ready to bind to another molecule of the substrate.
d) The substrate binds to the active site of the enzyme.

• A. c, a, b, d
• B. d, b, a, c
• C. a, b, c, d
• D. d, c, b, a

Hint:

Always start with substrate binding to the active site and end with product release. This simple logic narrows down the options immediately.

Answer 1

The Correct Option is B

Step 1: Understanding the Problem:
The catalytic cycle of an enzyme's action involves a specific sequence of steps that explain how a substrate is converted into a product using the induced-fit model.
Step 2: Approach and Formula:
Evaluate the standard catalytic cycle of enzymes, identifying the correct chronological order: Substrate binding $\rightarrow$ Enzyme shape alteration $\rightarrow$ Bond breaking/forming $\rightarrow$ Product release.
Step 3: Detailed Explanation:
The correct sequential steps are:
1. The substrate first binds to the active site of the enzyme, fitting into the active site. (Statement d)
2. The binding of the substrate induces the enzyme to alter its shape, fitting more tightly around the substrate. (Statement b)
3. The active site of the enzyme, now in close proximity to the substrate, breaks the chemical bonds of the substrate, and the new enzyme-product complex is formed. (Statement a)
4. The enzyme releases the products of the reaction, and the free enzyme is ready to bind to another molecule of the substrate. (Statement c)
Hence, the correct sequence is d, b, a, c.
Step 4: Final Answer:
The correct sequence is d, b, a, c.